A first conventional example of this kind of fuse unit is disclosed in a JP-A-2009-076408. A fuse unit 50, as shown in FIG. 11, includes a fuse element 51 which is formed of a conductive metal plate, and an insulative resin part 60 which is formed with insertion molding by using the fuse element 51 as an inserted component.
The fuse element 51, as shown in FIG. 13 in detail, includes a power supply connecting part 52 which is fixed to a battery post (not shown in the figure) via a battery connecting terminal (not shown in the figure), a first terminal connecting part 53 which has a bolt 70, a plurality of tab-shaped second terminal connecting parts 54, and a plurality of fusible parts 55 which are respectively arranged between the power supply connecting part 52 and the first terminal connecting part 53 and the second terminal connecting parts 54.
A U-shaped bolt insertion hole 53a is formed in the first terminal connecting part 53 of the fuse element 51. As shown in FIG. 14 in detail, a press fitting space 61 is formed of the insulative resin part 20 at the back side of the bolt insertion hole 53a. 
The bolt 70, whose rod 70b is inserted into the bolt insertion hole 53a, is fixed by press fitting the head 70a in the press fitting space 61 (refer to FIG. 12).
In a second conventional example, as shown in FIG. 15, pin entrances 80a where pressing pins (not shown) of a metal mold can enter are formed in the fuse element 80, and an insulative resin part (not shown in the figure) is formed with insertion molding by using a bolt 70A, which is positioned by the pressing pin (not shown in the figure) together with the fuse element 80 as inserted components. The inserted bolt 70A is fixed with the insulating resin which is filled around the inserted bolt 70A.